With interesting news stories on use of RFID in the supply chain still hard to come this week we will do a back to basics piece on active versus passive RFID tags, based on a recent piece on TechTarget.com by well-known technology writer George Lawton.
Supply Chain Digest Says... |
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| Passive tags today cost somewhere around 5 cents each. Active tags can be much more expensive, but Lawton says bluetooth-based active tags “cost as little as $1.00 at the low end of the market.” |
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Old news for RFID veterans, but we hope a nice tutorial for RFID newbies.
There is a clear line of demarcation between active and passive tags: the former includes a battery, so that they in some cases they can transmit their own signals. The latter does not, and instead relies on the energy of the RFID reader for the power to transmit its data.
Both typically transmit just an ID, like an electronic bar code, but other data in some cases can be stored and transmitted as well.
Lawton notes there are actually two types of active tags.
One containers a transponder that monitors within its read range for a request from an RFID reader and transmits when prompted (but at longer read ranges than passive tags).
Alternatively, an active tag can carry a radio beacon. In this type technology, the tag continuously sends a signal, and must therefore have a long-lived battery.
The article says active RFID tags can support a read range of more than 100 meters.
They are primarily uses to track valuable items, or re-usable logistics containers. Some active tag deployments are used in what are called Real-time Locator Systems (RTLS).
As noted above, a passive tag always depends on energy provided by a RFID reader to operate.
The lack of a battery greatly reduces the cost for chip manufacturers to produce an passive tag, such that they can potentially be used to track say millions of pieces of apparel, as some retailers are doing today.
Their smaller size also mean they can be delivered in many form factors, such as a label or price ticket.
Read ranges vary depending on the configuration, and can be from a few inches to 10 or more feet.
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CATEGORY SPONSOR: SOFTEON |
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Passive tags today cost somewhere around 5 cents each. Active tags can be much more expensive, but Lawton says bluetooth-based active tags “cost as little as $1.00 at the low end of the market.” But some active tags can cost several dollars each or more.
Lawton wraps up his informative piece by offering some thoughts on use cases for each type of tag:
• An active RFID tag captures supply chain data like humidity from perishable cargo.
• An active RFID setup can track the movement of valuable assets around a facility, such as medical equipment, repair carts or specialized tools.
• Active RFID is ideal for tracking assets over a wide area, such as automatically following the movement of a single company's containers at a busy shipping yard.
• Passive RFID is the best choice when changing batteries is impractical. For example, passive RFID is a good choice for livestock management.
• Passive RFID works well for tagging individual products for inventory control.
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